There is a pin in the top of the crankcase, and a notch in the top of the sleeve. Line those two up, and you'll be fine.

As for your exhaust manifold, running sluggish would most likely be caused by running with no gasket. Also, what kind of material did you use to seal the engine? how long did it sit after sealing before you actually fired it up? Did you tighten the head screws in an X pattern?

If all those answers are yes, and you've got the sleeve lined up properly with the crankcase, your culprit is definitely the exhaust gasket-unless your weather's changed, in which case it could be caused by improper tune.

Also, I forgot to mention to check all the o-rings in your carb. if you replace em, grease em before you install. Associated Green Slime works well (normally used for shock o-rings, but it prevents leaks in almost any seal with an o-ring and a moving part)